1. Field of the Invention
The present invention relates to the art of electrical connectors, and more particularly to electrical connection between a conductive contact of an electrical connector and a contact pad of a substrate.
2. The General Background
A microelectronic package typically interconnects with a substrate member, such as a motherboard, a printed circuit board or an interposer, through the use of an electrical connector. A variety of connectors are used in the microprocessor industry, most of which provide a relatively quicker and easy interface between the microelectronic package and the substrate.
Connectors are available with various mounting technologies, including surface mount technology (SMT) and compression mount technology (CMT). SMT socket connectors use standard reflow-soldering methods for mounting to the substrate. With higher pin counts, increased force is needed for the microelectronic package to make contact, and the solder connection must be capable of withstanding this larger force. Since the solder connection alone is not a reliable mechanical means of strength, the SMT technology is limited by the package pin count. In many cases, SMT has been used in combination with pin/socket interconnects, where the insertion/extraction force has been optimized and other means of mechanical rigidity has to be provided in addition to solder strength.
CMT is very popular with high-density devices. In addition to the same layout as SMT configuration, CMT footprints require four or more mounting holes and two or more alignment holes. These holes are placed around the SMT contact pads of the substrate, which makes the footprint larger. The greatest advantage of CMT socket connectors is that they can be easily assembled and removed using mechanical hardware that makes the rework cost close to zero.
In mounting conductive contacts of the socket connector onto holes of the substrate, the conductive contact tip profile is critical for the hole defined on the contact pad of the substrate, when the conductive contact wipes across the contact pad of the substrate. That is because, if the shape of the conductive contact tip is designed to have a sharp surface or edges, the sharp surface or edges of the contact tip could reduce the contact durability due to the interference between the contact tip and the hole of the substrate. Therefore, it is contemplated that the shape of the contact tip should be designed to be within the hole of the substrate for enhanced contact durability between the contact tip and the hole of the substrate.